Fuse



May 10, 1949. c. LAURlTsEN FUSE' 3 Sheets-sheet 1 I Filed April 2, v1943 26 /la l2 I3 wvENToR BY CHARLES 6 LAURITSEN 7 AT oRNEY May '10,I 1949. c. c. LAURITSEN FUSE Filed April 2, 1943 3 Sheets-Sheet 2 b 86a a6 a4 84 84 -V INVENTOR CHARLES 6'. LAUF/TSE f May l0, 1949. c. c. LAURlTsEN y 2,469,352

I FUSE l Filed April 2, 194s s sheis-sneet 5 7L 7a 67a y 2 i 5a 7/`% 7/ y 931 9;

i i l 90 75 :I `-l` jx A. 74 7,4 E .W- 7 n 85 874%? 87 aan aa i 4 //l/W/ lNV-ENTOR Y cHARLEsa/.A-un/TSEN Patented May 10, 1949 UNITED STATS ATENT OFFICE FUSE Application April 2, 1943, Serial No. 481,648

i Claims.

This invention relates to fuzes and more particularly to a novel hydrostatically armed fuze for underwaterv explosive devices, which comprises safety means for maintaining the fuze unarmed, and a device normally locking the safety means in its safe position and operable hydrostatically to release the safety means and permit firing of the fuze. The new fuze may be made in a simple and compact form and is positive in operation and safe to handle.

One object of the invention resides in the provision of a novel hydrostatically armed fuze which is simple and compact in construction by reason of its inclusion of a bell-crank lever forming part of the arming device. A fuze made in accordance with the invention comprises a bell-crank lever having one arm normally locking a safety means in its safe position to prevent firing of the fuze, the other arm lying adjacent a diaphragm, or the like, operable by fluid pressure to move the lever and release the safety means so as to permit ring of the fuze. In the preferred construction, the safety means are normally held in the safe position by a pair of opposed bell-crank levers having corresponding arms interlocked with the central portion of the diaphragm to prevent movement of the levers independently of the diaphragm. With this construction, the lever connection between the diaphragm and the safety means may be made in a symmetrical form occupying a relatively small space, and because of the symmetry of the levers, sidewise blows on the fuze tending to move one of the levers away from the safety means also tend to move the other lever toward the safety means so as to insure against movement of the latter from its safe position.

Another object of the invention is to provide a fuze of the character described having a firing pin and dual safety means including a gate normally rendering the firing pin ineffective and a striker head normally securing the pin against operation, both of which are held positively in their safe positions by the hydrostatic device and are released by operation of the device. Preferably, the gate and head are locked in their safe positions by opposed arms of the bell-crank levers, the free end portion of each arm looking one of the safety means and the intermediate portion of each4 arm locking the other safety means.

A further object of the invention resides in the provision of a novel fuze having a firing pin and a'striker head for securing the pin against operation and movable by either head-on or side- Wise impact of the fuze to `release the :tiring pin.

Another object of the invention is to provide a hydrostatically armed fuze including novel means for preventing accidental operation of the hydrostatic device.

These and other objects of the invention may be better understood by reference to the accompanying drawings, in which Fig. 1 is a longitudinal sectional view of one form of the new fuse;

Fig. 2 is a sectional View on the line 2 2 in Fig. 1;

Fig. 3 is a longitudinal sectional view of a moclied form of the fuze;

Fig. 4 is a similar view of still another form of the fuze, and

Fig. 5 is a side view partly in section showing a modification of the fuze illustrated in Fig. 4.

Referring to the drawings, I have shown for illustrative purposes an embodiment of my invention for use in antisubmarine explosive projectiles. The fuze is adapted to be mounted in the nose portion of the projectile and to detonate the high explosive charge in the projectile casing on impact with a submerged submarine.

The fuze, as shown, comprises a cylindrical casing I0 containing a hollow cylindrical body II which is mounted in spaced, concentric relation to the casing wall on a flange IIa integral with the body at its rear end. The flange I Ia ts closely in the casing and -is supported on its front face by a set of sleeves I2 disposed lengthwise in the casing and secured by posts |3 extending through the sleeves. At their rear ends, the posts project through the sleeves and are threaded in the fiange, while the front ends of the posts are threaded in the nose portion of the fuze to be described presently. The body I I is formed with a longitudinal bore for receiving a firing pin having a point I4 at its rear end and a shank Ma, extending forwardly from the point through the bore. An operating spring I 5 is coiled around the shank and is compressed between a flange I6 on the pin and a shoulder in the bore. At its front end, the body I I is formed with hollow concentric bosses I'I and I8, the inner boss I8 having openings for receiving a set of ball bearingsV` I9. The bearings are disposed partly in the boss I8 where they contact a bevelled surface on a cam 20 which is connected to a reduced portion of the ring pin at its front end, the reduced portion partly defining an annular recess 2I adjacent the bearings. The ball bearings I9 are normally held against the cam 20 by a striker head 22 having a rearwardly extending hollow boss formed with an internal annular recess 23 for receiving the bearings. The striker boss terminates between the bosses II and I8 on the body II and has an external shoulder 24 abutting against the front end of the outer boss I'I. It will be observed that the bearings I9 support the striker head and are held by the head on the cam 2|] to lock the ring pin in a retracted position against the spring I5. In its rear f-faceglthe body I I* `has .a transverse channel-*26"containinga safety gate 21, the'gate having an opening 28 for receiving a semi-cap (not shown). The gate is slidable in the channel 26 and is normally locked, by means to be described presently, at one end of the channel in a safe position (Fig. 2) so as "tooiset the opening 28 a substantial distance from the 'ring pin'-I4, whereby ring the semi-cap due to accidental operation of the ring pin islprevented. Movement of the gate to its armed position is effected by compression springs 29 seated in longitudinal bores in the gate anda having caps 30 on their J= outert ends engaging Athe -inner wallV of the casing. AThe 1ring= pin` assembly includingflange' I I a isUheldiiniithercasingf'by a retaining ring' V`3I threaded in the rear end of the casing. A disc `32ismeunted`in the` centralopening of the reitainingfring onthe `rearf-face'fofl the= flange I la and the gate 2'I and-`has a central'opening 33 i alined with the ring pin. 'llhe' disc` 32 is clamped against the flange Half-bya booster capi-34 threaded in` -the 1 retaining ring and containing the usual booster charge, such as tetryl (not j'shown),Fioridetonating-thewmain charge in the projectile.

l1 kIntermediatef its endsgthe gate `v21 is formed with slots 36 in its side walls forreceiving the land w i are provided `'intermediate 'their ends f'iwith shoulders i391 a'nd"39a;n respectively, disposed ldirectlylinlfront .offthestriker 'harige-124 *and closely adjacent thereto.; iItwilllbe apparent that whenf `'the lever I' arms 4$31 and 31a. are inf their innermost `positionsgtheshoulders 39 and 39a prevent:movement-ofthestrikerhead 22 due to limpact of Lthe fuze, while therear ends" of the llever armsengage in the'g'ate slots 35 'so as to L lockv thekgate 'positively infitssafe position against the actionL of springs' 29.

--HIn-the front endof ftheicasing I0 is a split 'nose discll made up-of -two'sections which are -l'separated to form a transversefsloti 4I yfor receiv- -ingtlre` bases of the bell crank levers SIAa'nd 31a. '.The levers are pivotally -mounted onpinsf42 extendingacross the slot 4I and held at 4their endsinI the-opposed sections of the discvll, *the pinsfhaving "suitable shoulders yfor holding the #disc-sections in expandedi positions against the innerfwalloftheteasing; Therear face ofthe `nose disc'40"engagesfthe adjacent ends of the rsleeveslI'Z, and the vfront ends of the posts I3 t are threaded into the nose disc.

Apre-stressed diaphragmllll is seated on lthe 4front end l of 'thel casingV and `isY 'clamped in posirtion around? its periphery .by a nose caprithreaded on'the `outside of the casing. The inner `faceofthe nose cap isrecessed to form achamber 43 adjacent thediaphragm, and the''chamber communicatesthrougha; centralurecess 41 inthe oapwith'radial passages 48 extendingithrough the side wall of the cap. The diaphragm is` normally dished outwardly-as-shownfbut when;` it islsubjeoted; onits l`outer face to a' .uid pressure wardly adjacentthe diaphragm andare confined at their free ends between the diaphragm and the head of the button 5U, whereby the arms are r interlocked with the diaphragm. The button projects through the diaphragm and is con- -nected thereto by anipple 52 screwed on the front tend of the .button vand loosely received in the recess'li'l. A safety Wire 53 extends through the 'radial passages 4B and through an alined opening in the nipple 52 so as to lock the diaphragm positively in its pre-stressed position. One end of the safety wire is bent around the side of the nose cap, asshown at 53a,- -while the other-end is provided withaloop 53bbent around the' oppositesiderot thenose cap and lyingflat against i the front -faceof 4thecap; sothat the -wire is held `securely in the cap.

A -ring`rf55`-is slidably==mounted l'on vthe outer cylindrical surface-ofthe body l'I land isengage- H able at its rear end with-inclined camhsurfaces f 5G on the bell-crank; levers.""I-he frontl end of el il is ventedtotheinsde of the projectile-through aport 62in the casing-wall.

that" the #gate `2'I- and striker` 22.` are docked-n ltheir safel` positions. `Also, A the diaphragml is locked in itspre-stressed positicnrbyr the wire53 the ring is engageable with similar-cam `surfaces 511cm the levers.

the usetof the-new-fuzejy the casingnr` is secured -in a suitable' recess `in the `nose portion -of .the projectile casing,and for-this1purpose` I provide the nose --capI 45 vwith-` an externally -threaded course 59 whiohfmay-Abe screwed-into Athe recess.` A` sealing "gasketl imay nbeinserted between afange 6I 'on thenose cap and the `rim ofi the lfune i opening to seal" -the linteriorv t of the projectile.y `Prefera`w.bly,=the interior-of `the casing In' uthe Anormal `.condition of they fuze; -thel lever arms 3-'I and 31a areheld in *theirrinnermost positions by the diaphragm through `the-buttorri52, so

so that the fuzemay be handledsafely without danger of accidental 'operation of the-diaphragm.

Before theprojectile is directedto the 'targati the `wire '15% is withdrawn from the passages-48 and thenipple52 so asto releasethe'diaphragm; -the loopl53b `serving asa lhandle for this purpose.

As lthe wire isilwithdrawn, it cleans' the" passages 43vand thereby insures proper owofwater into the chamber `It as the proj ectile' Ymoves `through :ward movementof Ithe lever arms-31 -and 31d due,"for example, toA spinninglof the projectile.

"When the `nose of `the -bomb1strikes '-the water, .the resulting force of reverse setba'ckcauses`the ringr55 rto move forwardly `against 1the` cam surfaces 51 on the levers where it alsoprevents :accidental outward movement? ofwthe lever arms.

and 37a.` are preventedfrom lmoving outwardly exceptby a-considerablefforce onfthe leverssuilcient to: slidethei-ring to fan- 'intermedatenpcsition by the cam'action yof the surfaces 561or 51.. Itv

projectile moves to a greater depth. When theA pressure on the front face of the diaphragm is sufficient to overcome its pre-stressing and to slide the ring 55 rearwardly through action of the cam surfaces 51, the diaphragm snaps to its opposite position against the concave face of the nose disc and moves the lever arms I and sla rearwardh7 on the pivots 42. As a result, the lever arms 31 and 31a move outwardly to the dotted line positions shown in Fig. 1 and release the striker head 22 and the gate 21. The gate is then moved to its armed position by the springs 29 so as to aline the semi-cap in opening 28 with the ring pin I. Preferably, the gate is locked in its armed position by a detent 62a mounted in the ange IIa. and urged into one of the gate recesses 36 by a compression spring 63.

Upon movement of the lever shoulders 39 and 33a away from the striker ilange 24, the striker remains on the ball bearings I9 as long as the fuze moves through the water without striking an object. However, when the fuze strikes an under-water object head-on, the resulting impact cau-ses the striker head to move forwardly in the casing due to the inertia of the head. Accordingly, the ball bearings I9 are forced inwardly against the cam 20 by the rear edge of the striker recess 23, with the result that the ring pin is retracted further against the action of the operating spring I5, and the bearings move into the annular recess 2|. vThe striker head is thus released from the bearings and falls against the nose disc lill, permitting the bearings to move outwardly through boss I8 by the action of the cam 20 and spring I5. The ring pin, therefore, is released and moved by the spring l5 with a snap action against the semi-cap (not shown) in the gate 21, and the semi-cap res through the opening 33 so as to detonate the charge in booster 313 and explode the projectile. In the event that the projectile should strike the under-water object with a glancing blow, the resulting sidewise impact causes the striker head 22 to pivot on the end of the outer boss I1, which is rounded to permit such action. As the striker pivots, the ball bearing (or bearings) opposite the pivoting point is displaced inwardly, against the spring action of cam 2D, by the rear edge of the striker recess 23, and the latter rides over the displaced bearing (or bearings) whereby the striker is released and the firing pin is actuated. Thev sensitivity of the striker head assembly is governed by the weight of the head, the strength of the ring spring I5, the height of the rear wall of striker recess 23 which moves over the bearings. and the smoothness of the working surfaces. The sensitivity to sidewise impact is also dependent upon the length of the striker head, which determines the moment arm of the force tending to pivot the head on the end of boss I1.

The new fuze is safe against accidental operation due to dropping or jolting, because the bellcrank levers hold the striker and the safety gate positively in place until the levers have been forced outwardly by hydrostatic pressure on the diaphragm. The symmetry of the leversis such.

thatthe eect thereon of sidewise blows is neutralized for the reason that when a blow tends to move one of the levers outwardly it also tends to move the other lever inwardly, the interlocking button 5I?, however, preventing independent movement of the levers. Similarly, the eiects of shaking the fuze are cancelled out by the opposing action of the levers.

When the projectile strikes the water surface, it is immediately decelerated and a dynamic water pressure is built up on the nose for a fraction of a second, during which time the diaphragm tends to operate the levers and arm the fuze. If arming should occur-.while the .deceleration is still suicient to release the striker 22, the fuze would re on or shortly after impact with the water, but such premature arming is prevented partly by the time lag required to operate the diaphragm and arming mechanism and partly by the action of the safety sleeve 55 in increasing the pressure required to operate the diaphragm. By properly proportionng the effective area of the diaphragm, the fuse may be made to arm at approximately any desired depth. While the speed of the projectile in the water has some eifect on the arming depth, due to the resulting dynamic pressure on the diaphragm, the effect is relatively small due to the arrangement of the ports G8 in the side of the nose cap. Since the diaphragm is relatively heavy and in its collapsed position is completely supported by the nose disc 4I), the fuze remains operative at substantial depths, at least to the extreme depths to which submarines can submerge.

When the fuze is subjected to a strong forward acceleration, as in firing the projectile from a gun, the lever arms 31 and 31a may tend to rotate about their pivots in such a direction as to permit arming, but premature movement of the levers is prevented by the restoring force of the diaphragm and by the action or the safety ring 55 on cam surfaces 51. Since the holding force of the ring against the cams 51 is proportional to the acceleration, no amount of acceleration can arm the fuZe.

The fuze shown in Fig. 3 comprises a cylindrical casing 5d containing a hollow body 65 which has an axial passage for receiving a firing pin E55. At its rear end, the body has an external flange 65a which ts closely in the casing so as to support the main part of the body in concentric relation to the casing wall. A safety gate 61 is slidable in a transverse slot in the rear face of the body 65, the gate being similar to the gate 21 shown in Figs. 1 and 2 and having a semi-cap (not shown) adapted to be engaged by the iiring pin. When the semi-cap is alined with the ring pin and the latter is operated, the cap fires through an opening 68a in a disc 68 mounted on the rear face of the flange 55a over the safety gate, the blast being directed into a booster charge in a container G9. The booster container is threaded into the rear end of the casing against the disc 63 to hold the parts in the casing.

Normally, the safety gate 51 i-s-locked in a safe position wherein the semi-cap is offset laterally from the ring pin and the opening 68a so that accidental operation of the pin cannot re the semi-cap and detonate the booster charge. The gate is locked in its safe position by a wire 10 extending transversely through the gate, the ange 65a andthe casing, the wire having a loop 10a serving as a handle for withdrawing the wire fromfthe' casing to release` the gate whenrthe,

accepta fuze is to be operated. The gate is-alsotloclred in its safe positionby the` arms 1l of a pair of opposed, bell-crank; levers, the free ends of the. arms normally extending..into slots 61a `inthe opposite sides; of the gate. The freeend portions` of the arms 1I lie in diametrically opposed slots 12 in the flange 65a, whereby the arms are movable radially in the casing and are guide'diin.

their movements.

The bell-crank levers' 1l are pivoted onpins 1li` mounted in a split discv 15 in the nose of theicas'- ing. The rear'face` of the dis'ci15 engages and supports the front end of the hollow body 65 `and has a hollow boss 15a telescoping. in a similar boss on the hollow body. Within the` body 65' and the split disc 15 is a compression spring 16 coiled around the firing pin and seated at its rear end against a shoulder ia` onthe pin. The-firing pin is` providedwith a similar shoulder 66h to the rear of thelshoulder 66a, and between the shoulders is a sel'l of ball bearings 11 mounted lin openings inthe side wall of the hollow `body 65. The bearings 11 are normally held in the yannular space between the shoulders 56a and 66h by a striker ring 18 having a beveled cam surface 18a engaging the bearings, the ring 1li` extending around the hollow body 65 and being tted closely in the fuze casing. A sleeve 19 extends around the hollow body 65 between its flange 65a, and' the striker ring 18, and the ends of the sleeve are seated on concave cam surface i-` and 80a on the ring and iiange, respectively. The ring 18` is locked in position on the bearings 11 by shoulders 1Ia on the bell-crank levers.

A nose cap 82 is secured on the frontend of the casing 64 and has an externally threadedcou-rse 82a which may be screwed into a suitable receptacle in the projectile casing (not shown). The cap 82 also has an internal flange B2b for retaining the nose disc 15 in the casing. Within the nose cap B2 is a exible, pre-stressed diaphragm 83 which is clamped around its periphery by a plug Slt threaded in the nose cap and having a hollow boss `lilla on its front end. The plug 84 has a recess defining a chamber 85 in front of the diaphragm, and the chamber communicates through the hollow boss 84a with radial passages 84D extending to the outside of the casing. A safety wire 86 extends through the passages `llb and through a pin 81 connected to the central portion of the diaphragm, so that the latter isnormally locked in its pre-stressed position, the wire `having a loop 86a,` at one end` for use in removing the wire to release the diaphragm. The arms 88 of the bell-crank levers extend inwardly adjacent the diaphragm and engage the front end of the ring spring 16.

In operation, the safety wires 1liY and 881 are removed prior to firing ya projectile containing the fuze. When the projectile is fired, it travels through an air trajectory and strikes the water nose-Erst, and during this time the safety gate 61 isI locked in its safe position by the free ends of lever 1l", and the striker ring 18 is locked against movement by the lever shoulders 1`I`a. The levers i are held in their locking positions by the forward thrust of spring 16 on the lever arms 88, whereby the safety gate and the striker ring remain locked in their safe positions after impact of the' projectile with the water surface. As the projectile moves through the water, the passages 84h permit entrance of water into the ch-amber 851, the water pressure in the chamber increasing with the' depth to which: the projectile moves. When the water pressure on` the diaphragm is suicient to overcome` its prestressing,` 4the diaphragm is snapped to a position` of` opposite curvature against thecon'caveifaceof nose disc 15` and the inner ends of the lever arms 88. Asa result, the arms 1l are move'dwoutwardly on their pivots 14 against the action of spring 16,5thereby releasing thesafetygate A'and'striker` ring. l The gate is `then moved to its armedlposition in which the 'semicap (not shown) is alined with the firing pin and the opening 68a;

On release of theA striker ring A18, the latter continuesto beheld by the ball bearings 11 against sleeve 19, `but when the projectile `strikes an un-l derwater target head-on, the striker` ring 18 moves 4forwardly under the force of reverse set back andv displaces the bearings: 11" inwardly against shoulder afand spring 16. The striker ls thus released from i the bearings and moves against the rear face'of dise 15;` The bearings 11 are thereupon forced outwardly by spring 16 acting through shoulder 66a, so as torelease the firing. pin which is then `actu-ated by the spring to rethe cap in `gate 61 and explode the booster charge. In the event'that the `projectile strikes the target a glancing blow, the resulting sidewise impact causes sleeve 19`to move laterally between the cam surfaces 8u and 80a, the cam surfaces acting to translate such lateral movement of the sleevel into a forward thrust on the striker ring 18; The ring is thus forced over the bearings 11 to release the firing pin, as previously described.

The fuze shown inl'ig.` 4 is similar to that illustrate'd in Fig. 3 except for the arrangement of the firing pin and thestriker ring. As shown in Fig. ll, the fuze includes a firing pin 90 having a single shoulder 9| normally engaged by the ball bearings 'l1y whichlock the pin in a retracted position against the compression spring 16.. The bearings 11` are normally held in their locking positions by aring 92 having a beveled cam surface 92a engaging the bearings, the ring 92 being normally lockedagainst the bearings by shoulders 93' on the levern arms 1l. When the lever arms are moved outwardly by the water pressure on diaphragm 83; the safety gate 61 is first released sovthat. it moves to its armed position before the shoulders g3 release ring 92. Accordingly, when the farms 1l complete their outwardI movement and release ring 921, the latter is urged rearwardly by the action of spring 15 on the bearings 11, whereby the bearings are forced outwardly and the firing pin is snapped against the semi-cap in gate B1..

A ymodification of the fuze shown in Fig. 4 is illustrated in Fig. 5. As there shown, the fuze casing 614e has a nose cap 82C containing -a prestressed diaphragm 83o, the central portion of which is r'eenforced by a disc 95. The diaphragm is iclamped' 'around its periphery by a plug 84o threaded in the nose cap, the plug being recessed to provide a chamber o in frontof the diaphragm. Threaded in the plug 8`4c are frangible horns ab" projecting forwardly from the fuze.` The horns may be made of a plastic material, or the like, and their inner end portions are formed with axial passages 91 communicating with chamber 85o.. In operation, when one of the horns 96 strikes an under-water target, the horn is broken by the impact. As a result, water enters the chamber85cthrough the passage 91 in the broken horn, they pressure of the water forcing thev diaphragm to a position of opposite curvature against: the lever arms 81 (Fig. 4). The levers are thus actuated to release the operating elements It will be observed that all of the forms of the new fuze, as illustrated, are armed hydrostatic-ally, and the forms shown in Figs. 4 and 5 are red under hydrostatic control while the other forms are impact-fired. It is to be understood that the invention is not limited to the constructions illusn trated but is susceptible of various modifications within its scope. For example, instead of arranging the diaphragm for operation by water pressure, it may be made to operate by the gas pressure from a rocket motor adapted to propel the projectile, as by mounting the fuze between the projectile and the rocket motor so that the diaphragm chamber may communicate with the pressure chamber in the motor, and in the preceding description and the appended claims, the term hydrostatic is intended to include within its range of equivalents any gaseous medium,

I claim:

1. A fuze comprising a firing device, safety means normally maintaining the firing device ineffective and movable to an operating position to render said device effective, a pair of opposed bell-crank levers each having one arm locking the safety means in its normal position against move ment, a diaphragm adjacent the other arm oi each lever and operable hydrostatically to move the levers for releasing the safety means, and a member on the central portion of the diaphragm engaging the free end portions of said .last arms and confining said free end portions between the diaphragm and said member, whereby the levers are interlocked with the diaphragm.

2. In a fuze having a firing pin, the combination of a hollow body in which the pin is slidable, a hollow boss on the body, a c'am on the pin disposed in the boss, a striker head, a hollow boss on the head surrounding said rst boss and having a recess in its inner wall, ball bearings mounted in openings in the side wall of said first boss and engaged in said recess and with the cam, said bearings being held by the head against the cam to lock the pin against operation and being held by the cam in said recess to support the head on the body, and biasing means for operating the pin and urging the cam against the bearings, the head being pivotable on the body upon sidewise impact of the fuze to force at least one of the bearings inwardly against the spring action on the cam and thereby release the head, whereby the bearings are movable outwardly by the cam to release the pin.

3. A hydrostatically armed, impact red fuze comprising a casing, a body in the casing having a longitudinal passage extending lengthwise of the casing, a firing pin slidable in the passage, biasing means for urging the pin slidably along the passage to detonate the fuze, bearing means mounted in the body, a striker head normally holding the bearing means against part of the pin for locking the pin in a retracted position against the biasing means, the biasing means acting through the pin to hold the bearing means in position to support the head, a pair of opposed bell-crank levers in the casing on opposite sides of said body and each having one arm locking 'the head against movement on the bearing means, and a diaphragm in the casing adjacent the other arm of each lever and operable hydro statically to move the levers and release the head, whereby the head becomes movable upon subsequent impact of the fuze to displace the bearing means and thereby release the pin.

4. A hydrostatic'ally armed, impact red fuze comprising a casing, a hollow body in the casing, a firing pin slidable in the body, a striker head in the easing normally locking the ring pin in a retracted position, a pair of opposed bell-crank levers in the easing on opposite sides of said body and each having one arm locking the head against movement, a diaphragm in the casing adjacent the other arm of each lever and operable hydrostatically to move the levers and release the head, the head being movable upon operation of the diaphragm and subsequent impact of the fuze to release the ring pin, and a ring slidably mounted on the body and normally engaging the levers to secure the same against movement independently of the diaphragm, the ring being movable by the diaphragm through the levers to release the levers.

CHARLES C. LAU'RITSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Dlate 806,026 Unge Nov. 28, 1905 1,224,414 Powers May 1, 1917 1,309,769 Nowell July 15, 1919 ,1,514,743 Taylor Nov. 11, 1924 1,617,674 Dieter Feb. 15, 1927 1,768,678 Froelich July 1, 1930 1,788,856 Bossone Jan. 13, 1931 1,959,401 Woodberry May 22, 1934 FOREIGN PATENTS Number Country Date 503,561 France Mar. 20, 1920 103,681 Germany June 20, 1899 310,549 Germany Feb. 5, 1919 

